You'll need to study up on both liquid and dry food measurements and weights and then do some math. For example, how many teaspoons are in your 'container' of nutmeg (this is where you'll need to learn how many teaspoons/tablespoons, etc are in both liquid and dry ounce). Let's say the nutmeg container contains 12 dry ounce teaspoons and that the container cost $12.00. Since you want to calculate the cost for 1 teaspoon of nutmeg from a 12 teaspoon container you divide it by 12 which would equal $1.00 per teaspoon.

Maybe someone else here can explain it differently and better but the bottom line is you're going to need to learn weights and measurements and do some math. ;-)